CN1168232C - Method and apparatus for overlaying two CDMA systems on same frequency bandwidth - Google Patents
Method and apparatus for overlaying two CDMA systems on same frequency bandwidth Download PDFInfo
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- CN1168232C CN1168232C CNB008127638A CN00812763A CN1168232C CN 1168232 C CN1168232 C CN 1168232C CN B008127638 A CNB008127638 A CN B008127638A CN 00812763 A CN00812763 A CN 00812763A CN 1168232 C CN1168232 C CN 1168232C
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/69—Spread spectrum techniques
- H04B1/707—Spread spectrum techniques using direct sequence modulation
- H04B1/7073—Synchronisation aspects
- H04B1/7075—Synchronisation aspects with code phase acquisition
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
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- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/24—Radio transmission systems, i.e. using radiation field for communication between two or more posts
- H04B7/26—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile
- H04B7/2662—Arrangements for Wireless System Synchronisation
- H04B7/2671—Arrangements for Wireless Time-Division Multiple Access [TDMA] System Synchronisation
- H04B7/2678—Time synchronisation
- H04B7/2687—Inter base stations synchronisation
- H04B7/2696—Over the air autonomous synchronisation, e.g. by monitoring network activity
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/24—Radio transmission systems, i.e. using radiation field for communication between two or more posts
- H04B7/26—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile
- H04B7/2662—Arrangements for Wireless System Synchronisation
- H04B7/2668—Arrangements for Wireless Code-Division Multiple Access [CDMA] System Synchronisation
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J13/00—Code division multiplex systems
- H04J13/0007—Code type
- H04J13/004—Orthogonal
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Abstract
In order to align the timing of an overlay base station to the timing of an existing base station, a sync unit (128) is introduced into the system. The sync unit (128) has a first receiver configured to receive a first signal, the first signal having a first CDMA channelization. The first receiver is configured to produce an indication of a timing of the first signal. The sync unit (128) also has a second receiver configured to receive a second signal, the second signal having a second CDMA channelization. The second receiver is configured to produce an indication of a timing of the second signal. The sync unit also has a time error detection unit configured to compare the timing of the first signal and the timing of the second signal to determine a relative timing offset thereof.
Description
Background of invention
I. invention field
The present invention relates to communication system.Especially, the present invention relates to overlapping code division multiple address communication system.
II. description of related art
Wireless medium has become one of main means that transmit speech information and numerical data in the modern society.In wireless communication system, normally single base station is transmitted into a plurality of remote units with signal.For at the coarse multi-path wireless send channel of antagonism when a plurality of remote units provide signal, modulation and encoding scheme that valid data transmission and subscriber channelization are provided have been developed.Generally, when each signal was launched with synchronization timing in the base station, the work of these schemes was the most effective.For example, in typical code division multiple access (CDMA) system, distinguish each signal by using different codes.From the base station under the situation of remote unit emission, these codes are the orthogonal code group normally, as the Walsh function.If corresponding to the emission misalignment of the orthogonal channel emission corresponding to another channel, the property of orthogonality of code will be degenerated so, this emission will produce serious the interference mutually with other emission.
Fig. 1 is the representative instance of terrestrial wireless communication system 10.Fig. 1 shows three remote unit 12A, 12B and 12C and two base stations 14.In fact, typically wireless communication system can have more remote unit and base station.In Fig. 1, remote unit 12A is shown is shown as the mobile telephone unit that is installed in the automobile.Fig. 1 has also shown laptop computer remote unit 12B and the fixed location remote unit 12C that for example can find in wireless local loop or meter reading system.In prevailing embodiment, remote unit can be the communication unit of any kind.For example, remote unit can be portable portable unit, as the portable data cell of personal digital assistant or as the fixed position data cell of meter reading equipment.Fig. 1 shown from the base station 14 to the forward link signal 18 of remote unit 12 and from remote unit 12 to the base station 14 reverse link signal 20.
In the following discussion, in order to help explanation, the present invention is described with reference to known Radio Link industrial standard.In fact, General Principle of the present invention can directly apply to many multi-address communication systems.Following discussion hypothesis is according to the system works described in TIA/EIA/IS-95-A and the growth thereof, the content of this standard is be entitled as " the Mobile Station-Base Station Compatibility Standard forDual-Mode Wideband Spread Spectrum Cellular System " of telephone industry association announcement, be commonly referred to IS-95, be incorporated herein by reference.
In typical wireless communication system as shown in fig. 1, some base stations have a plurality of sectors.Multi-sector base stations comprises a plurality of antenna and treatment circuits independently of independently transmitting and receiving.Principle described here is applied to each sector and the single sector stand-alone base station in the multi-sector base stations equivalently.Therefore, in the following description, can suppose that term " base station " is meant the sector in multi-sector base stations or the single sector base stations.
In the system that uses IS-95, remote unit uses all base station communications in common band width and the system.The use of common band width has increased adaptability, and provides lot of advantages for system.For example, the use of common band width makes remote unit can receive the signal of communication from a more than base station simultaneously, and the emission individual signals, receives for a more than base station.Remote unit is distinguished the signal that receives from various base stations simultaneously by using the spectrum CDMA corrugated nature.
In wireless system, the number of calling out when can handle, it is very important making the power system capacity maximization.If specified minimum acceptable signal quality, so just can calculate the upper limit of passing through the number of users of base station communication simultaneously.By some simplification, equation 1 has provided the necessary emitted power amount of remote unit:
Wherein:
N is the number of the remote unit of working in the common footprint territory;
R is a mean data rate, supposes all remote units all the same;
W is a spreading rate;
N
0Be that the thermal noise layer of base station adds the interference from the non-power controlled source;
Be the required energy of each noise spectral density in the remote unit, suppose all remote units all the same; With
α is the interference and coupling coefficient from all other overlay areas.The upper limit of number of users is commonly referred to the extreme value capacity of system simultaneously, when the denominator of equation 1 is 0, provides this value.The ratio of actual user's number and extreme value capacity is defined as the load of system.When actual user's number approached the extreme value capacity, load approached 1.Approach the latent instability state that 1 load means system.Labile state can cause the degeneration of speech quality performance, higher error rate, the handover of failure and lost-call.In addition, along with the increase of load, the required power output of remote unit also increases.Because the power output of remote unit is limited,, make that the user on the outer rim of unloaded overlay area no longer can launch enough power, with receptible signal quality and base station communication when the base station load is heavy so the big young pathbreaker of base station coverage area shrinks.Equation 1 is particularly suitable for reverse link.Therefore, a comparable equation that is suitable for forward link is arranged, it has comparable effect.For forward link, along with the increase of load, the required power output in base station also increases.
Owing to these reasons, preferably the number of users of limiting access system makes load be no more than the particular percentile of extreme value capacity.In case being system load, a kind of method of restriction system load arrives a predetermine level with regard to the denied access system.For example, if load is increased to more than 70% of extreme value capacity, so preferably refusal is extra connects the request of starting, and avoids accepting to exist the handover of connection.
When two cdma systems were worked in common bandwidth, load result that these are identical and time and Phase synchronization were still very important.If two systems are overlapping, and do not note their fundamental character, the capacity of generation may be quite little.Especially for forward link, the signal of base station quadrature normally wherein.For example, the forward link waveform described in the above IS-95 is mutually orthogonal.If overlapped signal group and existing sets of signals are not quadratures, the reduction of capacity may be quite big so.In order to keep orthogonality, must make two mutual time synchronized of system.In addition, therefore the load that the capacity of two systems also relates to first system will reduce the capacity of second system as the interference of second system, and therefore the load of second system will reduce the capacity of first system as the interference of first system.
The use of pilot signal will improve the capacity of forward link.Pilot signal can be used for catching and channel estimating, as the weighting of timing, phase place, power control and receiving symbol.Other signal of base station has known and constant phase alignment with respect to pilot signal.For fear of a plurality of pilot signals of emission, preferably keep constant phase alignment with respect to overlapping channel.
When using second cdma system in existing system, existing system does not have the ability that is connected with second type system usually.Therefore, existing system does not provide output usually, or accepts input, and these actions are required with the coordination load synchronously between two systems of acquisition.On the contrary, new system can be designed to have this overlay structure.In order to reduce to use the cost of second overlapping system, it is very important avoiding revising existing system.
Therefore, need a kind of system and method to be used for overlapping two cdma systems on the same frequency band width in this area.
Summary of the invention
For overlapping second cdma system on existing system, need the timing of the signal of each system's emission of calibration.For fear of revising existing system, can use the signal of lock unit reception from first and second systems.By the timing of comparison signal, produce the error signal of expression timing slip.Signal of timing error and the coupling of second cdma system, and can be used for regulating second system regularly, to reduce two time differences between the system.In some cases, calibrate the phase place of two systems in a similar fashion.
When the overlapping existing system of second cdma system, the capacity of each system is subjected to the restriction of load in another system.In another embodiment, lock unit is the power of one group of signal of two system's emissions of energy measurement also, and determine their grade of load.
Description of drawings
Fig. 1 is the block diagram of typical terrestrial wireless communication system.
Fig. 2 is the spectrogram that the spectrum signature of cdma2000 and IS-95 system is shown.
Fig. 3 illustrates the block diagram that can be used for realizing basic structure of the present invention.
Fig. 4 is the block diagram of lock unit of the present invention.
Fig. 5 is that wherein overlapping system uses the block diagram of the cellular system of Auxiliary Pilot Channel.
Fig. 6 is the schematic diagram that the use of orientation point antenna is shown.
Fig. 7 is that explanation is according to phase locked flow chart of the present invention.
Fig. 8 is the flow chart that illustrates according to load control of the present invention.
Detailed description of the present invention
When developing the third generation, broadband, code division multiple access (CDMA) system in the coverage that generation cdma system morning formerly is provided, make the frequency spectrums of operation of broadband system and existing system overlapping normally favourable.For example, can use 1X pattern, spreading rate overlapping with the old generation IS-95 system that also uses spreading rate 1 .2288Mcps (bandwidth is about 1.25MHz) as the cdma2000 of 1.2288Mcps (bandwidth is about 1.25MHz).Cdma2000 also has the 3X pattern, and the spreading rate that it uses is 3 * 1.2288Mcps (bandwidth is about 3.75MHz).A kind of in the cdma2000 3X pattern has multi-carrier forward link, IS-95 system or cdma2000 1X system that it can an overlapping old generation.
Fig. 2 is the spectrogram that the forward link spectrum signature of cdma2000 and IS-95 system is shown.With a channel of 3X pattern work, frequency spectrum 102,104 and 106 is represented the frequency spectrum of three IS-95 or cdma2000 1X mode channel in the frequency spectrum 100 expression cdma2000s.Frequency spectrum 102,104 and 106 is also represented each carrier wave of cdma2000 3X multicarrier system.For this overlapping system is suitably worked, two systems make two systems not cause excessive phase mutual interference with public timing working.If the use Common Pilot Channel, two systems use common phase to launch its forward link Code Channel so, and this common phase is aimed at the phase place of common forward link pilot channel.In addition, because the shared identical bandwidth of these systems, so the combination load of two systems must keep below the work threshold value, to keep the stability of a system.
Fig. 3 illustrates the block diagram that can be used for realizing basic structure of the present invention.Mobile switching centre (MSC) 110 makes cellular system and public switch telephone network (PSTN) coupling.MSC 110 is coupled to one or more base station controllers (BSC) 112 of existing system.BSC 112 provides the control as one group of base station of base station transceiver subsystem (BTS) 114 and so on.BSC 112 provides controlled function, for example forward link signal is distributed to base station transceiver subsystem, and the reverse link signal that receives from base station transceiver subsystem is carried out signal combination.Base station transceiver subsystem as BTS 114, is dispersed in the overlay area of system usually, provides service to the relevant base station overlay area.BTS 114 provides coding and modulation, and the further feature of physical link so that produce radio frequency (RF) signal, is launched on the Radio Link of existing system, existing system such as IS-95 system or with the cdma2000 of 1X or the work of 3X pattern.Base station transceiver subsystem is directly coupled to antenna usually, diversity antenna group or antenna array, antenna 122 as shown in Figure 3.
Except existing system, also show overlapping system among Fig. 3.Though can develop other enforcement, in Fig. 3, overlapping system is worked under the control of MSC 110.MSC 110 is coupled to overlapping base station controller 116, and this controller provides the control of one group of overlapping base station receiver of overlapping BTS 118 to as shown in Figure 3 and so on.In the example of Fig. 3, overlapping BSC 116 is connected to identical MSC 110 with existing BSC 112.Yet each has now can be connected to different MSC with overlapping BSC.Overlapping BTS 118 is according to the 2nd CDMA agreement, as the IS-95 system or with the cdma2000 of 1X or the work of 3X pattern, produces and also receives wireless link signals.
In order to keep common phase and timing, can launch the signal of each system's emission by community antenna.Therefore, combiner 120 makes existing BTS 114 and overlapping BTS 118 be coupled to antenna 122.As shown in Figure 3, combiner 120 will have the output combination of the power amplifier (not shown) of BTS 114 and overlapping BTS 118 now.Yet, general, implement in can be in the emission chain multistage any one-level of combiner 120.For example, in one embodiment, combiner 120 is at the intermediate frequency place, work in Analog Baseband or at the digital baseband place.
Similarly, in structure shown in Figure 3, combiner 120 makes antenna 122 be coupled to the low noise amplifier (not shown) that has now among BTS 114 and the overlapping BTS 118.Yet in another embodiment, combiner can be connected other position that receives in the chain.In another embodiment, the RX path of existing base station 114 and overlapping base station 118 is independently of one another.For example, Fig. 3 show existing and overlapping BTS combination transmit and receive part.Yet transmitting and receiving part can separate, and also can use different antennas.
Lock unit 128 has impelled the introducing of overlapping system.In one embodiment, lock unit 128 is coupled to independently antenna 126, and this antenna is arranged in the overlay area of antenna 122.In another embodiment, lock unit as directional coupler, obtains to be used to extract the signal energy of timing, signal phase and load by using coupler in the emission circuit between combiner 120 and antenna 122.In another embodiment, lock unit obtains regularly and phase information by a pair of coupler, and one of them coupler is in the emission chain or emission circuit of existing base station, and another coupler is in the emission chain or emission circuit of overlapping base station.In scope of the present invention, the emission chain is the some parts of BTS hardware itself, and the emission circuit is the feeder line that outputs to antenna from the BTS intermediate power amplifier.Generally, can both obtain to transmit, wherein can obtain to determine timing, phase place, the required adequate information of load from any part.When using, needn't use single position for all information from information that the emission chain of BTS obtains.For example, can obtain timing signal, can obtain power signal from another part of BTS from the part of BTS.Yet,, between the signal of the position of acquired information and aerial radiation, have error so if use other antenna.The result of these errors is the accuracy reductions that possible make setting-up time, set phase place or definite load.These results are that to understand the person skilled in the art of theory of the present invention known.As shown in Figure 3, lock unit 128 also is coupled to overlapping BTS 118.Yet in another embodiment, lock unit 128 can be coupled to existing base station 114, and non-overlapped base station 118.Yet general lock unit 128 is convenient to the time and the Phase synchronization of two systems, and need not the additional input or the output of existing system.The effect of lock unit 128 is time and the Phase synchronization that make the time of overlapping base station and phase place and existing base station.
For the signal that keeps existing BTS 114 emissions orthogonality between signals with overlapping BTS 118 emissions, according to medium-long range unit, respective coverage areas territory sentient, BTS 114 and 118 timing must be aligned with each other.In cdma2000, only need to aim at regularly, with the orthogonality of maintenance with the IS-95 system.Yet other system also may need the registration signal phase place.In addition, in order to use Common Pilot Channel, between existing system and overlapping system, must aim at phase place.
For example, when cdma2000 and IS-95 system are overlapping, should make about ten sixths of Code Channel time alignment PN chip or within about 50 nanoseconds.Along with the increase of time alignment error, the signal of existing base station and overlapping base station is more and more non-orthogonal.Non-orthogonal signal is interfering with each other, and causes lower power system capacity.
In one embodiment, overlapping system and existing system use same pilot channel.In this embodiment, the phase place of each CDMA Code Channel of overlapping BTS 118 emissions must with existing BTS 114 pilot transmitted phase aligned, because remote unit uses existing BTS 114 pilot transmitted signals to form the phase reference value, with the data-signal of demodulation from overlapping BTS 118.
Fig. 4 is the block diagram of lock unit 128.In one embodiment, lock unit 128 comprises pilot signal receiver 140.The structure of pilot signal receiver quite is similar to the structure of remote unit, to be implemented in the known technology that receives pilot signal in the cdma system.In addition, lock unit 128 comprises overlapping channel receiver 142, and it is used to receive the channel from overlapping base station.For example, in cdma2000, overlapping channel receiver 142 (it also can be constructed according to known technology) can be used for receiving Forward Common Control Channel (F-CCCH), forward broadcast control channel (F-BCCH), or any other signal of overlapping base station.Preferably, continuous monitoring of emission signal.Pilot signal receiver 140 produces regularly and phase signal.Overlapping channel receiver 142 also produces regularly and phase signal.In one embodiment, producing individual signals represents regularly and phase place.In another embodiment of the present invention, wherein do not need phase place, only need to obtain timing information.
Phase discriminator 144 compares the phase signal of pilot signal receiver 140 outputs and the phase signal of overlapping channel receiver 142 outputs, and produces the error signal of phase difference between these signals of expression.The structure of phase discriminator 144 can be according to many known devices, to realize determining the technology of phase error or phase difference.In another embodiment, lock unit can be monitored other channel of existing base station, as paging channel or synchronizing channel.In another embodiment, the pilot signal of overlapping BTS 118 emission lock units 128 monitoring, another channel of existing BTS 114 emissions of lock unit 128 monitoring.
The phase error signal of lock unit 128 outputs is coupled to the phase error input of overlapping BTS 118.Overlapping BTS 118 uses phase error signal to revise the phase place that overlapping BTS 118 is transmitted, to reduce the size of phase error.According to the individual design of overlapping BTS 118, can realize this process with a lot of known method.For example phase error can be used for controlling voltage controlled oscillator (VCO) voltage controlled oscillator and can be used for being the one or more local oscillator frequencies of overlapping BTS 118 generations.Perhaps, in the analog or digital circuit that the error signal of lock unit 128 is controlled, can develop phase shifter or delay line.In another embodiment, the output of lock unit 128 can be coupled to existing base station 114, and is used to regulate its phase place.Usually, this process makes the signal of the existing BTS emission of phase aligned of overlapping BTS emission.Because the signal from existing BTS is aligned with each other, and also is aligned with each other from the signal of overlapping BTS, so this aligning has all signals of aligning effect of phase place to each other.
With very identical mode, lock unit 128 can be used for making the timing of overlapping BTS 118 to aim at the timing that has BTS 114 now.Time error detecting unit 146 in the lock unit 128 produces error signal, and this signal has reflected the relative timing of the output signal of existing base station 114 and overlapping base station 118.Usually, existing base station 114, and overlapping base station 128 comprises timing generator, this timing generator is configured to and can regulates, and makes that system time and universal reference are synchronous.The signal of timing error that lock unit 128 produces can be coupled to timing generator, to regulate the timing between existing base station 114 and the overlapping base station 118, makes timing error reduce.Because the signal from existing BTS is aligned with each other, and also aligned with each other from the signal of overlapping BTS, so this aligning has all signals of aligning effect of time to each other.
Overlapping another related on existing cdma system importance with second cdma system is the load that needs each system of control.Load is very important for determining the policy of entering.The policy of entering is meant the judgement that wireless system must be made, and described judgement allows to use the higher data rate about whether allowing to increase additional speech or data call.These enter policy increases or reduces load successively.As mentioned above, the number of general work traffic channel is represented the load of system, but it is not uncertain.Therefore, be sent to existing BSC 112 and MSC 110 simply to work traffic channel counting, and with this information from existing BTS 114, and be sent to overlapping BSC 116 and be ultimately delivered to the accurate estimation that BTS 118 can not provide system load from this.In addition, this scheme relates to the change of existing system.Yet, for fear of to each system enter restriction arbitrarily, the duplex measurement of preferably studying a kind of load is favourable.The duplex measurement of this load can be used for influencing the policy that enters of overlapping BTS 116 and existing BTS 114, and makes the total load of each BTS remain in the rational restriction.
In one embodiment, lock unit 128 also can be used for load information is offered overlapping system, and need not to change existing system.For example, power measurement unit 148 is coupled to antenna 126, and measures power existing and each forward link Code Channel that overlapping system produces.In addition, pilot signal receiver 140 is determined the power of pilot channel.According to this information, comparing unit 150 can be determined load indication α according to following equation 2.
Wherein:
α is the load indication, and it remains on less than 1, with indication systems stabilisation performance;
E
PIt is the energy of pilot signal;
I
CIt is the gross energy that comprises the forward link Code Channel of pilot channel;
It is the predetermined pilot channel fraction of guaranteeing the stability of system; With
Equal current pilot channel fraction.
In one embodiment, comparing unit 150 is indicated according to equation 2 computational loads, and this information is offered the overlapping BTS 118 that this value is used to enter algorithm.In one embodiment, before importing overlapping BTS118 into, existing BTS 114 uses the predetermined algorithm that enters in an identical manner continuously.
Refer again to Fig. 4, notice each channel of 148 pairs of existing systems of power measurement unit and the power of each forward link Code Channel of each channel measurement of new overlapping system.Therefore, with reference to figure 2, in one embodiment, the power of each the forward link Code Channel of each channel measurement shown in 148 pairs of the power measurement unit.
Pilot signal receiver 140, overlapping channel receiver 142 and power measurement unit 148, each all carries out the demodulation of signal.Therefore, in one embodiment, when single, can realize these modules effectively in the subdivision.In another embodiment, at least a portion of these units shared receiver hardware.
In the embodiment that just describes, existing system or overlapping system are launched single pilot signal.The remote unit of working in two systems can use common pilot signal, to determine can be used for the phase reference of demodulation traffic channel signal.In another embodiment, the operation principle of Auxiliary Pilot Channel can be applicable to existing system or overlapping system.Auxiliary pilot provides the remote unit demodulation signal that send overlapping base station used phase reference.
Fig. 5 is that wherein overlapping system uses the block diagram of the system of Auxiliary Pilot Channel.In Fig. 5.Overlapping BSC116 is coupled to overlapping BTS 160.Overlapping BTS 160 is coupled to orientation, some antenna 162.Directed, some antenna 162 provides the overlay area in the existing system overlay area.For example, Fig. 6 is the schematic diagram that orientation, the use of some antenna are shown.The overlay area of big zone 170 expression antennas 122, the overlay area of less overlay area 172 expression orientation point antennas 162.In real system, directed, some antenna can be used for providing the overlay area that mainly comprises specific high load area.For example, directed, some antenna can be used for providing the overlay area to football field, shopping mall or campus.In one embodiment, some antenna 162 can have the overlay area identical with antenna 122.In addition, unnecessary have the antenna of separation to use Auxiliary Pilot Channel.In this case, Auxiliary Pilot Channel can be used for providing phase reference for the signal that launch in mode shown in Figure 3 overlapping base station.In this embodiment, lock unit 164 provides the timing of existing base station 114 with respect to overlapping base station 118 or 162.
In this embodiment, the independent pilot tone of overlapping BTS 160 emissions and existing BTS 114 pilot transmitted signal in orthogonal.In the embodiment of the overlay area of overlapping BTS less than existing BTS, when remote unit from the overlay area 107 when moving to overlay area 172, according to known technology, remote unit is carried out the handover from the existing system to the overlapping system.In overlay area 172, remote unit uses overlapping BTS 160 pilot transmitted signals, as phase reference.Owing to this reason, the signal of overlapping base station 160 emissions no longer needs the Phase synchronization of the signal of existing BTS 114 emissions felt with remote unit.
When overlapping system uses auxiliary pilot and when not needing Phase synchronization between existing system and the overlapping system, though under the situation of the overlapping IS-95 of cdma2000 system, time synchronized is still very important, so that the orthogonality of signal to be provided.Therefore, in Fig. 5,166 needs of lock unit 164 and antenna provide time synchronization information to overlapping base station 160.
In certain embodiments, overlapping system 160 used pilot signals are used the Walsh sequence longer than existing BTS.For example, in one embodiment, the length of existing BTS 144 pilot transmitted signals is 64 chips, and the length that is used for launching the Walsh code element of pilot tones from overlapping BTS 160 is 512 chips.Use long Walsh sequence to allow to produce the pilot signal of a plurality of more quadratures, therefore, allow in system, to distribute more frequently Auxiliary Pilot Channel.The sequence number of submitting on September 8th, 1997 is 08/925,521 (' 521 application), be entitled as the additional information that can find in the U.S. Patent application of " Method and Apparatus for Providing Orthogonal Spot Beams; Sector and Picocells " about Auxiliary Pilot Channel, this application has transferred assignee of the present invention, and it is incorporated into this in full by reference.The method and apparatus that the additional pilots channel is provided has been described in ' 521 application, and described additional pilots channel is minimum to obtaining the influence of Walsh channel number.' 521 applications has been described and has been connected Walsh combined sequence and Walsh sequence complement code so that the method for auxiliary pilot reference sequences to be provided.
Fig. 7 illustrates according to phase locked flow chart of the present invention.The principle of Fig. 7 can directly apply to time synchronized.In frame 200, existing BTS 114 uses first CDMA Channelization by antenna 126 emission pilot signals.In frame 202, lock unit 128 receives pilot signal by antenna 126.In frame 204, overlapping BTS 118 uses second CDMA Channelization and launches information signals by antenna 122.This information signal can be traffic channel or other remote unit signal specific, and perhaps it can be a broadcast singal, as synchronous channel or paging channel emission.In frame 206, lock unit 128 is by antenna 126 receiving information signals.In frame 208, lock unit 128 compares the phase place of pilot signal and the phase place of information signal, and produces the phase error indication.In frame 210, overlapping BTS 118 is according to the phase place of phase error signal information signal that adjustment is launched.
Under the situation of time synchronized, can use, and the frame that produces signal of timing error replaces frame 208 timing ratio of the timing of pilot signal and information signal.Similarly, can launch the frame replacement frame 210 of the timing of information signal with adjusting.
Fig. 8 is the flow chart that illustrates according to an embodiment of load control mechanism of the present invention.In frame 220, existing base station 114 uses first CDMA Channelization by antenna 122 emission pilot signal and one or more information signals.In frame 222, lock unit 128 receives pilot signal by antenna 126, and the power level of definite pilot signal.In frame 224, overlapping base station 118 uses second CDMA Channelization by the one or more information signals of antenna 122 emissions.In frame 226, lock unit 128 receives and uses the information signal of first and second CDMA Channelization by antenna 126 emissions, and determines the power level of each information signal.In frame 228, lock unit 128 is determined load level according to power measurement values.In another embodiment, can be in overlapping BTS 118 or the determining of certain other position computational load.In frame 130, load level can be used for the standard that enters that definite overlapping BTS 118 uses the additional signal of the second CDMA Channel emission to enter.
With reference to figure 7 and 8, and other above-mentioned embodiment, use directional coupler or above-mentioned other signal energy coupling mechanisms can be realized the process by the second antenna picked up signal energy.
Can in other particular forms, realize the present invention and not break away from spirit of the present invention or substantive characteristics.For example, in one embodiment, overlapping system can be the system with narrower channel width, and existing system has the wideer channel of frequency band.In one embodiment, more than two systems are overlapped.In all respects, only consider that described embodiment is used for explanation, and it is nonrestrictive, therefore, following claim but not the scope of claims of the present invention has been pointed out in above description.Comprise equivalent meaning of claims and all changes in the scope in this scope.
Claims (45)
1. the method for overlapping second cdma system on first cdma system is characterized in that, this method may further comprise the steps:
Use the first CDMA Channel emission, first signal;
Use the second CDMA Channel emission secondary signal, at least a portion of the shared common frequency spectrum of wherein said first and second CDMA Channelization, and described first signal and described secondary signal are launched into the common footprint territory;
Acquisition is corresponding to the signal energy of described first signal;
Acquisition is corresponding to the signal energy of described secondary signal;
Based on the signal energy of described acquisition, the phase place of described first signal and the phase place of described secondary signal are compared, to produce the phase error indication; With
According to described phase error indication, adjust the phase place of the described secondary signal of emission.
2. the method for claim 1 is characterized in that, described first signal is a pilot signal.
3. the method for claim 1 is characterized in that, the step of launching described first and second signals comprises the step of launching described first and second signals by first antenna.
4. method as claimed in claim 3 is characterized in that, acquisition comprises the step that receives described first and second signals by second antenna corresponding to the step of the signal energy of described first and second signals.
5. the method for claim 1 is characterized in that, acquisition comprises the step of using coupler corresponding to the step of the signal energy of described secondary signal.
6. the method for claim 1 is characterized in that, described second CDMA Channelization has than the wide frequency spectrum of described first CDMA Channelization.
7. the method for claim 1 is characterized in that, described first CDMA Channelization has than the wide frequency spectrum of described second CDMA Channelization.
8. the method for claim 1 is characterized in that, described secondary signal is the remote unit signal specific.
9. the method for claim 1 is characterized in that, described secondary signal is an information signal.
10. the method for claim 1 is characterized in that, described secondary signal is a broadcast singal.
11. the method for overlapping second cdma system on first cdma system is characterized in that, this method may further comprise the steps:
Use the first CDMA Channel emission, first signal;
Use the second CDMA Channel emission secondary signal, at least a portion of the shared common frequency spectrum of wherein said first and second CDMA Channelization, and described first signal and described secondary signal are launched into the common footprint territory;
Acquisition is corresponding to the signal energy of described first signal;
Acquisition is corresponding to the signal energy of described secondary signal;
Based on the signal energy of described acquisition, the timing of described first signal and the timing of described secondary signal are compared, to produce the timing error indication; With
According to described timing error indication, adjust the timing of the described secondary signal of emission.
12. method as claimed in claim 11 is characterized in that, described first signal is a pilot signal.
13. method as claimed in claim 11 is characterized in that, the step of launching described first and second signals comprises the step of launching described first and second signals by first antenna.
14. method as claimed in claim 13 is characterized in that, acquisition comprises the step that receives described first and second signals by second antenna corresponding to the step of the signal energy of described first and second signals.
15. method as claimed in claim 11 is characterized in that, acquisition comprises the step of using coupler corresponding to the step of the signal energy of described secondary signal.
16. method as claimed in claim 11 is characterized in that, described second CDMA Channelization has than the wide frequency spectrum of described first CDMA Channelization.
17. method as claimed in claim 11 is characterized in that, described first CDMA Channelization has than the wide frequency spectrum of described second CDMA Channelization.
18. method as claimed in claim 11 is characterized in that, described secondary signal is the remote unit signal specific.
19. method as claimed in claim 11 is characterized in that, described secondary signal is an information signal.
20. method as claimed in claim 11 is characterized in that, described secondary signal is a broadcast singal.
21. the method for overlapping second cdma system on first cdma system is characterized in that, this method may further comprise the steps:
Receive first signal and one or more first information signal, described first information signal uses first CDMA Channelization and provides service to first overlay area;
Receive one or more second information signals, described second information signal uses second CDMA Channelization and at least a portion to described first overlay area that service is provided;
Determine the power level of described first signal;
Determine in the described one or more first information signal power level of each;
Determine in described one or more second information signal the power level of each; With
According to the described power level of described first signal and the described power level of described one or more first and second information signals, determine the load level at least a portion described in described first overlay area.
22. method as claimed in claim 21 is characterized in that, also comprises the step of launching described one or more first information signal and described one or more second information signals by first antenna.
23. method as claimed in claim 22 is characterized in that, receiving step comprises the step by the second antenna receiving signal energy.
24. method as claimed in claim 21 is characterized in that, receiving step comprises the step of using coupler.
25. method as claimed in claim 21 is characterized in that, also comprises the standard that enters that the information signal that uses described load level to determine to use the described second CDMA Channel emission enters.
26. method as claimed in claim 21 is characterized in that, described second CDMA Channelization has than the wide frequency spectrum of described first CDMA Channelization.
27. method as claimed in claim 21 is characterized in that, described first CDMA Channelization has than the wide frequency spectrum of described second CDMA Channelization.
28. method as claimed in claim 21 is characterized in that, described first signal is a pilot signal.
29. a cdma system is characterized in that it comprises:
First base station is configured to launch first signal;
Second base station is configured to launch secondary signal; With
Lock unit is configured to receive described first signal and described secondary signal, and is configured to determine the relative phase difference between them;
Wherein, described second base station also can be configured to adjust according to described relative phase difference the phase place of the described secondary signal of emission; And
Use described first signal of the first CDMA Channel emission, use the described secondary signal of the second CDMA Channel emission.
30. cdma system as claimed in claim 29 is characterized in that, also comprises first antenna, it is coupled to described first and second base stations, and is configured to launch described first signal and described secondary signal.
31. cdma system as claimed in claim 29 is characterized in that, described first signal is a pilot signal, and described secondary signal is an information signal.
32. a cdma system is characterized in that it comprises:
First base station is configured to launch first signal;
Second base station is configured to launch secondary signal; With
Lock unit is configured to receive described first signal and described secondary signal, and is configured to determine that the relative timing between them is poor;
Wherein, it is poor that described second base station also can be configured to according to described relative timing, adjusts the timing of the described secondary signal of emission; And
Use described first signal of the first CDMA Channel emission, use the described secondary signal of the second CDMA Channel emission.
33. a cdma system is characterized in that it comprises:
First base station is configured to launch first signal and one or more first information signal with first CDMA Channelization, and described first information signal provides service to first overlay area;
Second base station is configured to launch one or more second information signals with second CDMA Channelization, and at least a portion of described first overlay area of described second information signal provides service; With
Lock unit is configured to obtain corresponding to each power level in described first signal and described one or more first and second information signals;
Wherein, described lock unit also can be configured to determine the load level in described at least a portion of described first overlay area according to the described power measurement values of described first signal and the described power measurement values of described one or more first and second information signals.
34. cdma system as claimed in claim 33 is characterized in that, the standard that enters that described base station also can be configured to determine to use the information signal of the described second CDMA Channel emission to enter.
35. a lock unit is characterized in that it comprises:
First receiver is configured to receive first signal with first CDMA Channelization, and produces the timing indication of described first signal;
Second receiver is configured to receive the secondary signal with second CDMA Channelization, and produces the timing indication of described secondary signal; With
The time error detecting unit is configured to the described timing of described first signal and the described timing of described secondary signal are compared, and to determine relative timing skew indication, is used to adjust the emission timing of described secondary signal.
36. lock unit as claimed in claim 35 is characterized in that, described lock unit also comprises the antenna that is used to receive described first and second signals.
37. lock unit as claimed in claim 35 is characterized in that, described lock unit also comprises the coupler that is used to receive described first and second signals.
38. lock unit as claimed in claim 35 is characterized in that, the shared at least a portion hardware of described first and second receivers.
39. lock unit as claimed in claim 35 is characterized in that, subdivision when described first and second receivers are single.
40. lock unit as claimed in claim 35, it is characterized in that, also comprise phase error detection unit, be configured to the phase place of described first signal and the phase place of described secondary signal are compared, to determine relative phase skew indication, be used to adjust the transmitter, phase of described secondary signal.
41. lock unit as claimed in claim 35, it is characterized in that, also comprise power measurement unit, be configured to determine the power level of described first and second signals, and comparing unit, be used for determining load level corresponding to the overlay area of described first and second signals.
42. a lock unit is characterized in that it comprises:
First receiver, the one or more first information signals that are configured to receive first signal He have first CDMA Channelization, described first information signal provides service to first overlay area;
Second receiver is configured to receive one or more second information signals with second CDMA Channelization, and at least a portion of described first overlay area of described second information signal provides service;
Power measurement unit, be configured to determine in the power level of described first signal, the described one or more first information signals each power level and described one or more second information signal in each power level; With
Comparing unit is configured to determine the load level in described at least a portion of described first overlay area according to the described power level of described first signal and described one or more first or the described power level of second information signal.
43. a cdma system is characterized in that it comprises:
Use the device of the first CDMA Channel emission, first signal;
Use the device of the second CDMA Channel emission secondary signal, at least a portion of the shared common frequency spectrum of wherein said first and second CDMA Channelization, and described first signal and described secondary signal are launched into the common footprint territory;
Acquisition is corresponding to the device of the signal energy of described first signal;
Acquisition is corresponding to the device of the signal energy of described secondary signal;
Based on the signal energy of described acquisition, the phase place of described first signal and the phase place of described secondary signal are compared to produce the device of phase error indication; With
According to described phase error indication, adjust the device of the phase place of the described secondary signal of emission.
44. a cdma system is characterized in that it comprises:
Use the device of the first CDMA Channel emission, first signal;
Use the device of the second CDMA Channel emission secondary signal, at least a portion of the shared common frequency spectrum of wherein said first and second CDMA Channelization, and described first signal and described secondary signal are launched into the common footprint territory;
Acquisition is corresponding to the device of the signal energy of described first signal;
Acquisition is corresponding to the device of the signal energy of described secondary signal;
Based on the signal energy of described acquisition, the timing of described first signal and the timing of described secondary signal are compared to produce the device of timing error indication; With
According to described timing error indication, adjust the device of the timing of the described secondary signal of emission.
45. a cdma system is characterized in that it comprises:
Receive the device of first signal and one or more first information signals, described first information signal uses first CDMA Channelization and provides service to first overlay area;
Receive the device of one or more second information signals, described second information signal uses second CDMA Channelization and at least a portion to described first overlay area that service is provided;
Determine the device of the power level of described first signal;
Determine the device of the power level of each in described one or more first information signal;
Determine the device of the power level of each in described one or more second information signal; With
According to the described power level of described first signal and the described power level of described one or more first and second information signals, determine the device of the load level at least a portion described in described first overlay area.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US09/395,300 | 1999-09-13 | ||
| US09/395,300 US6882631B1 (en) | 1999-09-13 | 1999-09-13 | Method and apparatus for overlaying two CDMA systems on the same frequency bandwidth |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1373947A CN1373947A (en) | 2002-10-09 |
| CN1168232C true CN1168232C (en) | 2004-09-22 |
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| CNB008127638A Expired - Fee Related CN1168232C (en) | 1999-09-13 | 2000-09-12 | Method and apparatus for overlaying two CDMA systems on same frequency bandwidth |
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| EP (1) | EP1212851A1 (en) |
| JP (2) | JP2003509952A (en) |
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| CN (1) | CN1168232C (en) |
| AU (1) | AU7372400A (en) |
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| HK (1) | HK1047659B (en) |
| TW (1) | TWI239153B (en) |
| WO (1) | WO2001020817A1 (en) |
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| US6882631B1 (en) * | 1999-09-13 | 2005-04-19 | Qualcomm Incorporated | Method and apparatus for overlaying two CDMA systems on the same frequency bandwidth |
| US6314126B1 (en) * | 2001-01-12 | 2001-11-06 | Linex Technologies, Inc. | Spread-spectrum handoff and source congestion avoidance system and method |
| US8605686B2 (en) * | 2001-02-12 | 2013-12-10 | Qualcomm Incorporated | Method and apparatus for power control in a wireless communication system |
| US20040137416A1 (en) * | 2002-04-05 | 2004-07-15 | Yue Ma | System and method using adaptive learning components to enhance target advertising and customize system behavior |
| US8194703B2 (en) | 2002-08-07 | 2012-06-05 | Kyocera Corporation | Wireless communication system |
| US8364185B2 (en) * | 2005-04-18 | 2013-01-29 | Samsung Electronics Co., Ltd. | Method and system for synchronizing a clock for an adjacent network to a clock for an overlay network |
| KR100830163B1 (en) * | 2005-04-20 | 2008-05-20 | 삼성전자주식회사 | Apparatus and method for transmitting/receiving signal in a frequency overlay communication system |
| US7933561B2 (en) * | 2006-12-11 | 2011-04-26 | Apple Inc. | Wireless communications circuitry with simultaneous receive capabilities for handheld electronic devices |
| JP4606405B2 (en) * | 2006-12-18 | 2011-01-05 | 京セラ株式会社 | Wireless communication system control method, base station control method, and wireless communication terminal control method |
| US8325856B2 (en) | 2007-03-05 | 2012-12-04 | Qualcomm Incorporated | Coherent initial acquisition |
| US7818029B2 (en) * | 2007-04-11 | 2010-10-19 | Apple Inc. | Wireless communications circuitry with antenna sharing capabilities for handheld electronic devices |
| FI20085423A0 (en) * | 2008-05-08 | 2008-05-08 | Nokia Siemens Networks Oy | Synchronization in a mobile communication system |
| US8654625B2 (en) * | 2009-02-02 | 2014-02-18 | Lg Electronics Inc. | Method and apparatus for transmitting data performed by at least one base station in wireless communication system |
| US8219157B2 (en) * | 2009-03-26 | 2012-07-10 | Apple Inc. | Electronic device with shared multiband antenna and antenna diversity circuitry |
| US8208867B2 (en) * | 2009-04-09 | 2012-06-26 | Apple Inc. | Shared multiband antennas and antenna diversity circuitry for electronic devices |
| EP3291460B1 (en) * | 2015-06-25 | 2019-08-14 | Huawei Technologies Co., Ltd. | Method of synchronizing phases and device utilizing same |
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| US5224120A (en) | 1990-12-05 | 1993-06-29 | Interdigital Technology Corporation | Dynamic capacity allocation CDMA spread spectrum communications |
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1999
- 1999-09-13 US US09/395,300 patent/US6882631B1/en not_active Expired - Fee Related
-
2000
- 2000-09-12 JP JP2001524274A patent/JP2003509952A/en active Pending
- 2000-09-12 WO PCT/US2000/024956 patent/WO2001020817A1/en active Application Filing
- 2000-09-12 EP EP00961826A patent/EP1212851A1/en not_active Withdrawn
- 2000-09-12 BR BR0013934-3A patent/BR0013934A/en not_active IP Right Cessation
- 2000-09-12 CN CNB008127638A patent/CN1168232C/en not_active Expired - Fee Related
- 2000-09-12 AU AU73724/00A patent/AU7372400A/en not_active Abandoned
- 2000-09-12 KR KR1020027003323A patent/KR100760479B1/en not_active IP Right Cessation
- 2000-11-28 TW TW089118724A patent/TWI239153B/en active
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2002
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2010
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Also Published As
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| US20070147293A1 (en) | 2007-06-28 |
| US20050122917A1 (en) | 2005-06-09 |
| TWI239153B (en) | 2005-09-01 |
| JP2003509952A (en) | 2003-03-11 |
| CN1373947A (en) | 2002-10-09 |
| HK1047659B (en) | 2005-05-13 |
| US7397780B2 (en) | 2008-07-08 |
| KR100760479B1 (en) | 2007-09-20 |
| HK1047659A1 (en) | 2003-02-28 |
| BR0013934A (en) | 2002-07-02 |
| KR20020030819A (en) | 2002-04-25 |
| AU7372400A (en) | 2001-04-17 |
| WO2001020817A1 (en) | 2001-03-22 |
| US6882631B1 (en) | 2005-04-19 |
| US7212508B2 (en) | 2007-05-01 |
| EP1212851A1 (en) | 2002-06-12 |
| JP2011082972A (en) | 2011-04-21 |
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